CLIMATIC CHANGE AND ITS IMPACT ON THE CORN GROWING SEASON IN JALISCO, MEXICO

Abstract

The objective of this study was to quantify the changes in growing season (GS) and the thermal capacity (TC) of GS, during the period 1947- 1996 in Jalisco, Mexico. Using daily and monthly climatic data from 42 weather stations, the commencement (GSC), finalization (GSF) and duration (GSD) of growing season were estimated for the periods 1947-1971 and 1972-1996 using. FAO methodology and values of precipitation at 75 %. TC was calculated in growing degree days accumulated (GDDA) during GS. GDDA were estimated using maximum and minimum daily temperatures and considering a base temperature of 10ºC. Based on these calculations, geographical interpolations were carried out in order to generate state of GSC, GSF, GSD, and TC. The interpolations were developed with GIS IDRISI 4.1. The results showed that GSD had an average reduction of six days; since GSC was delayed two days and GSF was registered four days earlier. Reduction of GSD was associated with a decrement of probalistic precipitation of June, September, and October. Reduction of GSD yielded a diminished TC by 79 GDDA in average. It is concluded that GS and CT have a decreasing tendency, so by these years the agroclimatic conditions are less favourable for the rainfel agriculture in Jalisco, Mexico.